Charles is a good trainer, and a knowledgable guy who will evaluate your physique on its potential, he best identifies weak points and works almost exclusively trying to engage body parts from angles where they can neutralise other supporting muscles. Many people struggle to engage their backs, etc, he can sometimes assist with adjustments to minimise delt or arms compensating movement.
He will also honestly tell you what you need to do on whats required and whether it's worth you pursuing it. Appreciate its not rocket science, but he cops a bit of negative press. He's a very humble guy, certainly worth seeking out if you have pro ambitions . Appreciate there are many others who are probably even more knowledgable these days. But he pioneered it back in the 90s.